The conventional method of producing a sparkle finish using a powder coating is to add metal flake, e.g., aluminum, to the coating powder. As one method of producing a powder coating, metal flake is admixed with the coating powder and this admixture is applied, e.g., electrostatically, to a substrate. An improvement in this method is adhering the metal flake to the coating powder, such as is taught in U.S. Pat. No. 4,197,351.
There exist concern with the inclusion of metal flake in coating powders, particularly coating powders which are to be applied electrostatically, from a safety standpoint. Conductivity through the metal flake may cause shock, and, if carelessly used, may even result in dust explosions. Accordingly, there is a desire to provide a sparkle finish using other material than metal.
It was attempted to use glass flakes to produce a sparkle finish. Glass flakes are too fragile to be adhered to coating powders by conventional methods. Accordingly, it was attempted to admix glass flake with coating powder and apply this coating to a substrate. Essentially no sparkle effect was achieved.
The present invention is directed to using glass flake in a powder coating process to achieve a sparkle finish.